A radio access network (RAN) provides for radio communication links to be arranged within the network between a plurality of user terminals. Such user terminals may be mobile and may be known as ‘mobile stations’ or ‘mobile devices.’ At least one other terminal, e.g. used in conjunction with mobile devices, may be a fixed terminal, e.g. a base station, eNodeB, repeater, and/or access point. Such a RAN typically includes a system infrastructure that generally includes a network of various fixed terminals, which are in direct radio communication with the mobile devices. Each of the fixed terminals operating in the RAN may have one or more transceivers which may, for example, serve mobile devices in a given region or area, known as a ‘cell’ or ‘site’, by radio frequency (RF) communication. The mobile devices that are in direct communication with a particular fixed terminal are said to be served by the fixed terminal. In one example, all radio communications to and from each mobile device within the RAN are made via respective serving fixed terminals. Sites of neighboring fixed terminals may be offset from one another and may provide corresponding non-overlapping or partially or fully overlapping RF coverage areas.
RANs may operate according to an industry standard protocol such as, for example, an open media alliance (OMA) push to talk (PTT) over cellular (OMA-PoC) standard, a voice over IP (VoIP) standard, or a PTT over IP (PolP) standard. Typically, protocols such as PoC, VoIP, and PoIP are implemented over broadband RANs including third generation and fourth generation networks such as third generation partnership project (3GPP) Long Term Evolution (LTE) networks.
RANs may additionally or alternatively operate according to an industry standard land mobile radio (LMR) protocol such as, for example, the Project 25 (P25) standard defined by the Association of Public Safety Communications Officials International (APCO), the TETRA standard defined by the European Telecommunication Standards Institute (ETSI), the Digital Private Mobile Radio (dPMR) standard also defined by the ETSI, or the Digital Mobile Radio (DMR) standard also defined by the ETSI. Because these systems generally provide lower throughput than the broadband systems, they are sometimes designated narrowband RANs.
Communications in accordance with any one or more of these protocols or standards, or other protocols or standards, may take place over physical channels in accordance with one or more of a TDMA (time division multiple access), FDMA (frequency divisional multiple access), OFDMA (orthogonal frequency division multiplexing access), or CDMA (code division multiple access) protocol. Mobile devices in RANs such as those set forth above send and receive data (such as encoded voice, audio, and/or audio/video streams) in accordance with the designated protocol.
OMA-PoC, in particular, enables familiar PTT and “instant on” features of traditional half duplex mobile devices, but uses mobile devices operating over modern broadband telecommunications networks. Using PoC, wireless mobile devices such as mobile telephones and notebook computers can function as PTT half-duplex mobile devices for transmitting and receiving. Other types of PTT models and multimedia call models (MMCMs) are also available.
Floor control in an OMA-PoC session is generally maintained by a PIT server that controls communications between two or more wireless mobile devices. When a user of one of the mobile devices keys a PTT button, a request for permission to speak in the OMA-PoC session is transmitted from the user's mobile device to the PTT server using, for example, a real-time transport protocol (RTP) message. If no other users are currently speaking in the PoC session, an acceptance message is transmitted back to the user's mobile device and the user can then speak into a microphone of the device. Using standard compression/decompression (codec) techniques, the user's voice is digitized and transmitted using discrete auditory data packets (e.g., together which form an auditory data stream over time), such as according to RTP and internet protocols (IP), to the PTT server. The PTI server then transmits the auditory data packets to other users of the PoC session (e.g., to other mobile devices in the group of mobile devices or talkgroup to which the user is subscribed), using for example, one or more of a unicast, point to multipoint, or broadcast communication technique.
Narrowband LMR systems, on the other hand, operate in either a conventional or trunked configuration. In either configuration, a plurality of mobile devices is partitioned into separate groups of mobile devices. In a conventional system, each mobile device in a group is selected to a particular radio channel (frequency or frequency & time slot) for communications associated with that mobile device's group. Thus, each group is served by one channel, and multiple groups may share the same single frequency (in which case, in some embodiments, group IDs may be present in the group data to distinguish between groups using the same shared frequency).
In contrast, a trunked radio system and its mobile devices use a pool of traffic channels for virtually an unlimited number of groups of mobile devices (e.g., talkgroups). Thus, all groups are served by all channels. The trunked radio system works to take advantage of the probability that not all groups need a traffic channel for communication at the same time. When a member of a group requests a call on a control or rest channel on which all of the mobile devices at a site idle awaiting new call notifications, in one embodiment, a call controller assigns a separate traffic channel for the requested group call, and all group members move from the assigned control or rest channel to the assigned traffic channel for the group call. In another embodiment, when a member of a group requests a call on a control or rest channel, the call controller may convert the control or rest channel on which the mobile devices were idling to a traffic channel for the call, and instruct all mobile devices that are not participating in the new call to move to a newly assigned control or rest channel selected from the pool of available channels. With a given number of channels, a much greater number of groups can be accommodated in a trunked radio system as compared with a conventional radio system.
Group calls may be made between wireless and/or wireline participants in accordance with either a narrowband or a broadband protocol or standard. Group members for group calls may be statically or dynamically defined. That is, in a first example, a user or administrator working on behalf of the user may indicate to the switching and/or radio network (perhaps at a call controller, PTT server, zone controller, or mobile management entity (MME), base station controller (BSC), mobile switching center (MSC), site controller, Push-to-Talk controller, or other network device) a list of participants of a group at the time of the call or in advance of the call. The group members (e.g., mobile devices) could be provisioned in the network by the user or an agent, and then provided some form of group identity or identifier, for example. Then, at a future time, an originating user in a group may cause some signaling to be transmitted indicating that he or she wishes to establish a communication session (e.g., group call) with each of the pre-designated participants in the defined group. In another example, mobile devices may dynamically affiliate with a group (and also disassociate with the group) perhaps based on user input, and the switching and/or radio network may track group membership and route new group calls according to the current group membership.
Many so-called “public safety” or other private or government wireless communication systems provide for group-based radio communications amongst a plurality of mobile devices. In certain situations, important group calls may be associated with a particular area in which a responding officer or other type of user is located. Particular areas and their associated talkgroup may, in some instances, be defined by geofences, which help to establish virtual barriers based on a geographical coordinate system. For example, at an incident scene, a geofence and associated talkgroup may be established in an area associated with the incident scene, and a responding officer or other user may manually or automatically switch their radio to the associated talkgroup when arriving at the incident scene and crossing into the geofence. In an enterprise environment, a geofence and associated talkgroup may be established for retail and warehouse personnel, and an employee arriving at work may manually or automatically switch their radio to the associated talkgroup when arriving at work and crossing into the geofence.
However, as more geofences get created and associated with separate talkgroups, it becomes difficult for a user and mobile device located within multiple geofences at a same time and/or roaming into and out of several geofence regions which may partially or fully overlap, to keep track of which talkgroup(s) it should be or is already joined to and when to join a call occurring on one of those talkgroups.
Accordingly, what is needed is an improved method and apparatus for providing an intelligent and dynamic group scan capability across multiple overlapping geofence regions and their associated talkgroups.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.